4 pst status indicators, 5 recognition of valid pst signals, 6 rejection of pst signal – Flowserve MX Electronic Actuator SIL Safety IOM User Manual
Page 20: 7 actions on recognition of valid pst signal

Limitorque MX Electronic Actuator FCD LMENIM2350-01 – 9/13
20
FLOWSERVE PROPRIETARY INFORMATION
Use or disclosure of this information is subject to the restrictions on the title page of this document
7.3.3 Digital Output (Relay Contact) Configuration Options for PST
Status (S) alarm contacts configuration options include the following.
7.3.3.1 PST Active
This function shall be set when PST STATUS is active. This function shall be reset when PST STATUS is configured,
passed or failed.
7.3.3.2 PST Passed
This function shall be set when PST STATUS is passed. This function shall be reset with next PST move command.
7.3.3.3 PST Failed Target
This function shall be set when actuator failed to reach the PST target position. This function shall be reset with the next
PST move command.
7.3.3.4 PST Failed Return
This function shall be set when actuator reached PST target position but failed to return to the initial start position. This
function shall be reset with next PST move command.
7.3.4 PST Status Indicators
Table 7.1 - PST Status Indicators
PST Status
LCD Message
Not configured for PST
Input 1 configured as PST
STATUS OK
Active (test underway, result undefined)
PS ACTIVE
Failed to reach target after PST timer timeout
FAULT INDICATION (if any)
Failed to return to starting position after PST timer timeout
FAULT INDICATION (if any)
Passed
STATUS OK
7.3.5 Recognition of Valid PST Signals
A PST signal on INPUT 1 (Terminal 34) shall be interpreted as a valid PST command signal only when Input 1 is config-
ured as PST and PST is not currently active, and the current position is more than 2% away from the target position.
7.3.6 Rejection of PST Signal
A PST signal on INPUT 1 (Terminal 34, or D2) shall be interpreted as an invalid PST command signal, and actuator shall
not respond to such PST command signal when PST is active or if a fault exists that would prevent actuator movement
(see Section 3.1).
7.3.7 Actions on Recognition of Valid PST Signal
When valid PST command signal received on INPUT 1 (Terminal 34)
• PST status shall be set to Active.
• LCD indicates “PST ACTIVE.”
• Actuator shall move toward PST target position.
• When the actuator reaches target position ± 2%, actuator shall stop, wait for 5 to 10 seconds, and then return to its
starting position ±2%.
• Any status relay configured to change state on active PST shall assume its configured state.